Expression control for electric musical instruments.



M. L. SEVBRY & G. B. SINCLAIR.

EXPRESSION 001mm. FOR ELECTRIC MUSICAL INSTRUMENTS.

AAAAAAAAAA N FILED FEB 26, 1910.

' 1,125,746. Patented Jan. 19, 1915.

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M. L. SEVERY &: G. B. SINCLAIR.

EXPRESSION CONTROL FOR ELECTRIC MUSICAL INSTRUMENTS.

' APPLICATION FILED I'EB.25, 1910. 1,125,74 Patented Jan. 19, 1915.

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MASSACHUSETTS.

EXPRESSION CONTROL FQR ELECTRIC MUSICAL INSTRUMENTS.

l Specification of Letters Patented J anpl t), 1915;

Application filed February 25, 1910. Serial No. 545,963.

To all whom it may concern:

Be it known that we, MELVIN L. SEvEnY, of Arlington Heights, inthe county of Middlesex and Commonwealth of Massachusetts, and Gnome B. SINCLAIR, of Medford, in

said county and Commonwealth, both citi-- Zens of the United States, have invented certain new and useful Improvementsm EX- pression- Controls for Electric Musical Instruments, of which the following is a specibrated with the said expression rheostatsin any given position to sound with the de-.

gree of loudnessnecessary to correct musical balance. In other words, our unprovement is for the purpose of giving the instrument perfect gradation in expression.

Referring to the drawings forming part of this specification, Figure 1 is a cross section of our rheostat,showing other parts of the instrument in diagram. Fig. 2 is a perspective view of one of the elements of the rheostat. Fig. 3 is a perspective view of a coupled pair of saidelementsbut with the wiring thereof not shown. Fig. 4 is a perspective view, but with the intermediate section of the same broken away, of the rheostat box and brush carrier. Fig. 5 is an enlarged edge view of an element showing a lead therefrom. Figs. 6 and? are face views of the elements adapted for'two dif ferent notes. Fig. 8 is a. diagramshowing the plotted curves for the resistance to be given different notes and different volumes of the same note, This resistance variation is roughly indicatedby Figs. .6 and 7, in

whichFig. 6 shows a'pointof connection 4 the second five between the secondand third ten between the third and fourth; sixteen between the fourth and fifth, the total resistance being thirtyreight turns. In Fig. 7 there are shown to be respectively four, five, six, thirteen and twenty-onebetween the steps amounting... to forty-nine turns. Between the lowermost notes and the higher treble ones of the instrument, such differences are very largely magnified. .This' is shown in the chart (Fig. 8) where the vertical line representing the resistance for C is less than one tenth the .heightlof the line representing the resistance. for C. It should, therefore, be apparent that it is no simple matter not only to proportion the resists ancesifor the various notes in order to have them balance each other 1n sonorous effect atalli degrees of loudness, but also so to arrange the resistances as to produce proper graduations from soft to loud and vice versa. for equal movements of the'brushcarrying. member 16. For instance,- when the brushes 18 are moved from the first contactsup' to the second horizontal row, and so on up, each step of such movement should diminishso gradually the/loudness of the music that there may be no apparent break therein,-the correct interrelation between. the various notes of the instrument being secured at every point. This we have succeeded in accomplishing through our above described arrangement. Each of the said rheostat elements consists of a thin rectangular plate of insulating material 1 having wound thereon a multiplicity of turns of fine wire 2. This wire is preferably bare, but is wound so perfectly parallel as not to allow :contact between any of its several coils or turns.

At one edge of the plate 1, several of th winds or coils, preferably five are prolonged into extension loops 3, and each twisted more or less at such edge (as in Fig. 5) in order to retain such coils in place. These extension loops Sare to serve as lead wires varv the length thereof in a circuit.

lVe have discovered that if two notesare properly balanced for a certain amount of.

actuating current, so that neither will unpleasantly dominate the other,'and a definite resistance be cut into the circuit to one thereof to reduce its loudness, the same amount of res stance cutinto the others circuit may not afl'e t the latter to anywhere near the same extent. For instance if the current to each of two notes is reduced by one half, the loudness of one of the notes may be only slightly affected, while the other may be many times diminished in loudness, the difference depending chiefly upon factors referable to the pitch of the note. Further the same note is not uniformly affected by the same decrease in current throughout all degrees of its loudness. When it is being vibrated at its loudest, less resistance may be needed to reduce it one step, than to produce a similar decrement when it is vibrating softly. Furthermore the ideal relative degree of prominence of the various notes in a fortissimo passage is not by any means necessarily the correct balance for pianissimo passages. On the contrary, the proportion of one part of gamut to another, as for example bass to treble, may often, for ideal results, change with every change of loudness. This fineness of voicing it has hitherto been impossible to secure as the factors are so complex and intricate, but we have at last succeeded in attaining it. Having thus discovered these unforeseen facts, we have worked to produce a variable rheostat by means of which the player can automatically preserve a pleasing balance between all the notes of the instrument throughout the entire gamut from extreme loudness to extreme softness; and after much labor and experimentation we have finally succeeded in plotting curves (incompletely but approximately indicated by Fig. 8) for every note of the instrument, and all usual degrees of loudness of each note, by following which we can accurately determine the total amount of resistance wire 2 for each note of the scale, and the proper points in each element at which to cut in the loops 3. 1n winding the elements, therefore, the workman follows such plotted chart, applying a certain total number of winds of wire 2 to one plate 1; less to another; more to another, etc; making a certain number 01' winds before forming the first loop 3; certain other number to the second loop 3, and so on; the amount of resistance for every note and each degree of loudness of each note, becoming a matter of mathematical certainty, the size of the wire being varied as circumstances require.

A lead wire lbeingioined to the wire 2 at the extreme left hand end, as shown in Figs. 6 and 7, then the circuit between the right hand loop 3 and said wire at will comprise all the turns of the wire 2, while the circuits between the intermediate loops 3 and said wire l will embrace fewer turns, and consequently have less resistance therein. After the plate 1 has been wound as above set forth, with the loops 3 and lead 1 projecting therefrom, a suitable insulating material preferably in liquid form is laid over the wires2, either by means of a brush, by dipping the plate and windings in the liquid, or otherwise insuring the insulation of the wire; for we have found that in use without these precautions, the wire 2 becomes more or less elongated relative to the plate 1, either by expansion of the wire or shrinkage of the plate, and the turns get displaced and parts of the resistance thereby cut out. Two of these elements are then fastened to opposite sides of two thin bars 5, as by screws or rivets 6, and to the projecting ends of said bars is secured a cross piece 7 the outer edge of which is curved concentric with a point just beyond the opposite ends of the elements 1; and to this curved edge or face are fastened several contacts 9 equal in number to the sum of. the loops 3 on the two elements 1. In the lateral faces of this cross piece are formed grooves 10 into which the lead wire a and loo )8 3 are laid, each of them being suitably secured, preferably by solder, to a contact 9; the lead 1 and loops 3 of one element lying in grooves 10 at one side of the cross piece, and the lead and loops of the other element lying in the grooves at the opposite side.

In the top and bottom of the elongated box 11 are numerous transverse grooves 12 into which the coupled elements can he slid, the thin bars 5 fitting said grooves. and a longitudinal strip 13 limitin the distance to which said coupled elements go as shown in F g. 1. At the back of this box is rotata upported a longitudinal shaft 14, as

n .igs. 1 and 4, substantially concentric th the curved faces of the cross pieces 7; ant

L 1e arms 15 carrying at their free. ends a bar 16, preferably of angle-iron, to the outer face of which is secured an insulating strip 17, preferably wood, carrying the b ushes 18 whose extremities sweep t 1e said contacts 9 as said shaft is rocked.

The brush-carrying members are moved by means of gravity and a tension spring 19 and a link 20 extending to any suitable operating pedal, knee-swell or the like.

Each brush 18 is put into circuit with the current-source 28 through the elements comprising the wire 29, brush 30, pulsation devices 31, ii 4-, resistance coils 2, a wire 3, and the particular contact 9 with which said. brush may be touching; wire 21, electrcmagnet '22, wire 2%, contact 25, keycontrolled brush 26, and wire 27 back to said source. The magnetic impulses delivered to said electromagnet from said pulsation devices through said circuit are adapted to vibrate the sonorous body and the vigor of such. impulses and consequent loudness of such vibrations depend upon which contact 9 the brush 18 is engaging. Consequently, as the brush-carrying members are swung upon the cnds of said shaft are fixed up or down, the brushes 18 cut in or out several different degrees of resistance to the electromagnets 22, and not only enable the music to be well modulated in expression, but by the proper proportioning of the resistance of each element, as above recited, preserve a proper balance between the notes of the instrument throughout all changes in loudness thereof. 1

No claims are made in the present application to the rheostat proper as that forms the subject-matter of a divisional application for patent on rheostats, Serial No. 878.471, filed December 22, 1914.

What we claim as our invention and for which we desire Letters Patent is as follows, to wit:

1. The combination. with an instrument having electrical means for producing notes in musical relation, of an electrical expression-control for said means comprising a series of rheostats each individual to a note of said instrument and varying in ohmic value with the pitch of the note with which it is associated.

2. The combination with an instrument having electrical means for producing notes in musical relation, of an electrical expression-control for said means comprising a series of rheostats eachindividual to a note of said instrument, and meansfor simultaneously and unequally altering the resistance of the said individual rheostats.

3. The combination with an instrument having electrical means for producing notes in musical relation, of rheostats individual to the respective notes, and movable means for cutting in and out different degrees of resistance, equal movements of said means producing for the same note unequal changes in the amount of resistance associated with such note.

4. The combination with an instrument having electrical means for producing notes in musical relation, of a plurality of resistance members, each member individual to one of said notes, the resistance of said members varying according to the notes with which they are associated.

5. The combination with an instrument having electrical means for producing notes in musical relation, of a plurality of resistance members, each member individual to one of said notes, and containing a plurality of sections adapted to vary the amount of resistance of said member, corresponding sections of different individual members being of unequal resistance.

6. In a musical instrument, the combination of electrical means for producing notes in musical relation; and electrical'expression-controlling means individual to the respective notes, and adapted to vary the amount of current delivered to each noteproducing means and the consequent loudness of such note, said controlling means embracing means for giving successive varia tions'in resistance, different for the different notes, and unequal in amount for the various degrees of loudness of the same note.

7'. In a musical instrument, the combination of a series of sonorous bodies tuned in musical relation; a series of electromagnets for educing from said bodies their respecwhen moved with reference to the contact blocks to bring into or cut out of circuit with the respective electromagnets, electrical resistance differing in the different magnet circuits, and unequalin each magnet circuit for equal movements of the expression-control device.

8. A musical instrument comprising sonorous bodies of different pitches electromagnetically vibrated, and a movable expression control therefor having a movable device for shifting it, said expression control having rheostats whose increments of resistance for the same movement of said device increase as the scale is ascended.

9. A musical instrument comprising sonorous bodies electromagnetically vibrated, and a movable expression control therefor having a movable device for shifting it, said expression control having rheostats whose increments of resistance for the same movement of. said device increase as the resistance is increased.

10. A musical instrument comprising sonorous bodies of difierent pitches, electromagnets for their actuation, means embracing circuits for supplying said electromagnets with electrical pulsations, and means under the control of the operator for varying unequally the amount of current received by said magnets irrespective of the number of the magnets simultaneously energized, said means embracing rheostats individual to said circuits each differing from the others in'the aggregate amount of its resistance, and such aggregate resistances increasing in an increasing ratio as the scale is ascended.

11. A musical instrument comprising sonorous bodies of different pitches, electromagnets for their actuation, means embracing circuits for supplying said electromagnets with electrical pulsations, and means under the control of the operator for varying unequally the amount of current received by said magnets irrespective of the 4 1,125, 7&6

number of the magnets simultaneously en erg-ized, said means embracing rheostats individual to said circuits, said rheostats being arranged in steps for each circuit, and the amount of resistance between said steps varying in the several circuits, and progressively increasing as the scale is ascended.

In testimony that We claim the foregoing invention, We have hereunto set our hands this 29th day of January, 1910.

MELVIN L. SEVERY. GEORGE B. SINCLAIR.

lVitnesses: A. B. UPHAM, CHARLES GABRISON.

Copies -of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

WashingtomD. G. 

